(1) Field of the Invention
The present invention pertains to a hub ring employed in mounting a rotating shaft of an electrical device, for example an electric motor, to a supporting bracket. In particular, the present invention pertains to a hub ring that reduces or eliminates the transmission of vibration from the shaft to the supporting bracket and is provided with an integral locking mechanism that automatically secures the hub ring to the supporting bracket when the hub ring is positioned on the bracket without the need for separate attachment parts and/or fasteners.
(2) Description of the Related Art
Hub rings have long been employed in the prior art in mounting electrical devices such as electric motors to supporting brackets. Vibration damping hub rings are generally comprised of an inner, annular damper constructed of a resilient material such as rubber and an outer, annular ring constructed of a more rigid material such as plastic or metal. Hub rings are usually employed in pairs with the annular dampers of the hub rings being mounted over bearings or bushings mounted on the opposite ends of the motor shaft and the outer rigid rings of the hub rings being mounted on support brackets.
FIG. 1 shows one example of a prior art hub ring 12 mounted on a support bracket 14. The support bracket 14 is one of a pair of support brackets 14, 16 that support an electric motor 18 by supporting opposite ends of the motor shaft 22. In the example shown, each support bracket 14, 16 is constructed from a flat piece of metal that is stamped or in some other equivalent manner formed with a base portion 24 and an arm portion 26. As shown in FIG. 1, the arm portion 26 of each bracket is bent at a right angle relative to the base portion 24. When the base portion of each bracket is attached to a support surface, for example that of an electric appliance, each arm portion positions an arcuate support surface 28 of each arm at a vertical height above the base portion that is sufficient to support the electric motor 18 above each base portion. Although only one support surface 28 of the two bracket arms 26 is visible in FIG. 1, they are both configured in the same manner. At the opposite ends of the support surface 28 each arm is formed with a pair of outwardly projecting catches 32. Each of the catches 32 has a latch surface 34 on its underside.
The support brackets 14 shown in FIG. 1 are only one example of support brackets that have been employed in supporting electrical devices such as motors. There are many other types of support brackets that are used for the same purpose, however most have the common features of an arcuate support surface and a pair of latch surfaces at opposite ends of the support surface.
The support surface 28 of the bracket 14 to the right in FIG. 1 is shown supporting a prior art hub ring 12 attached to the bracket. FIG. 2 shows the prior art hub ring 12 removed from the support bracket. The hub ring 12 is basically comprised of an outer annular ring 36 constructed of metal, plastic or other similar rigid material and an inner annular damper 38 constructed of rubber or other similar resilient material. The outer ring 36 has a cylindrical peripheral surface with an annular groove 42 formed into the surface forming a pair of annular rims 44 at axially opposite sides of the groove. The groove 42 has an axial dimension or width that is sized to receive the support surface 28 of the bracket in a tight fit, preventing any axial movement of the hub ring 12 relative to the bracket 14 when the hub ring is mounted on the bracket. The annular damper 38 is molded, glued or secured to the interior surface of the outer ring 36 in some other equivalent manner. In the embodiment of the hub ring shown in FIG. 2, the damper is formed with four radially inwardly projecting surfaces 46 that are dimensioned to fit in tight friction engagement around the exterior of a bearing or bushing mounted on the shaft 22 of the motor 18. Alternatively, the interior surface 48 of the damper could be dimensioned to fit in tight friction engagement around the bearing or bushing supporting the motor shaft 22.
Referring back to FIG. 1, the prior art hub ring 12 is shown mounted on the right side support bracket 14 with the damper 38 engaging around a bearing 52 mounted on the motor shaft 22. The hub ring 12 is positioned on the support bracket 14 with the support surface 28 of the bracket engaging in the annular groove 42 of the ring. In the example shown in FIG. 1, the hub ring 12 is securely held on the bracket support surface 28 by a pair of curved straps 54 constructed of a rigid material such as metal, plastic or other similar rigid material. Each of the straps are the same and are formed with an elongated slot 56 adjacent one end and a fastener hole 58 adjacent the opposite end. In securing the hub ring 12 to the support bracket 14, the straps 54 are positioned on the bracket as shown to the right in FIG. 1 with the pair of arm catches 32 extending through the slots 56 of the brackets and with the fastener holes 58 of the brackets aligned at the top of the hub ring 12. A screw 62 and nut 64 fastener is then attached through the aligned holes 58 of the straps and is tightened down, thereby securing the hub ring 12 to the support bracket 14. This attachment process is repeated for a hub ring mounted on the motor shaft 22 at the opposite end or left hand end of the motor shown in FIG. 1.
FIG. 3 shows a variation in the prior art mechanism for attaching a hub ring to a support bracket where the pair of curved straps are replaced by a single strap 66 having an inverted U-shape. The single strap 66 is constructed of metal, plastic or other similar resilient material. It is formed with a pair of elongated slots 68 adjacent its opposite distal ends and with a U-shaped bend 72 at its center. The center U-shaped bend 72 gives the single strap a resiliency in addition to the resiliency of the material from which the strap is constructed. In securing the hub ring 12 to a support bracket 14 employing the single strap 66, one of the elongated slots 68 is first attached over one of the arm catches 32 of the support bracket and the strap 66 is stretched over the top of the hub ring 12. Stretching the strap 66 causes the U-shaped bend 72 to open slightly enabling the elongated slot 68 on the opposite end of the strap to pass over the other arm catch 32 and engage with the latch surface 34 of the catch, thereby attaching the single strap 66 onto the support bracket securing the hub ring to the support bracket. In a variation of this attaching mechanism, a screw and nut fastener 74 can be provided through the U-shaped bend 72. The fastener 74 can be tightened down to constrict the single strap 66 over the top of the hub ring 12 to further secure the hub ring to the support bracket 14.
FIG. 4 shows a still further variation of a hub ring 76 that is similar to the previously described prior art hub rings except that it is provided with an integral attachment mechanism. The hub ring shown in FIG. 4 is usually constructed of resilient plastic and includes a center ring 78 dimensioned to fit in tight friction engagement around a bearing or bushing 82 mounted on the motor shaft 84. An outer ring 86 surrounds the center ring 78 and is connected to the center ring by a plurality of curved, resilient spring members 88. The hub ring 76 is held to the support bracket 14 by integrally formed flexible attaching straps 92 that have slotted openings (not shown) near their distal ends. The attaching straps 92 are shown in their operative position in FIG. 4 securing the hub ring 76 to the support bracket 14. In at rest or free positions of the attaching straps 92 the resiliency of the straps moves them to positions that are spaced radially outward from the arm catches 32 of the support bracket. In attaching the hub ring 76 to the support bracket 14, the hub ring is first positioned on the support surface 28 of the bracket and one of the straps 92 is positioned over one arm catch 32 with the one strap engaging the latch surface 34 of the arm catch. The hub ring 76 is then rotated slightly causing the engaged strap 92 to stretch and the free strap 92 is stretched until its elongated slot (not shown) can be passed over the opposite arm catch 32 of the support bracket engaging the free strap with the opposite latch surface 34.
The prior art hub ring attachment mechanisms described above are disadvantaged in that they are difficult to secure to the support bracket 14. The hub ring shown in FIG. 1 is attached by first positioning the hub ring on the support bracket 14 and then holding the two curved straps 54 over the opposite sides of the hub ring while the bolt 62 is inserted through the aligned holes 58 of the straps. The nut 64 is then threaded on the bolt 62 and tightened down to secure the hub ring 12 to the support bracket. Thus, the attachment mechanism shown in FIG. 1 has the drawback of having multiple parts which makes the installation and removal of the attachment mechanism difficult and time consuming, especially in environments having limited space, for example in the interior of a household appliance.
Despite the benefits over the multiple part attachment mechanism of FIG. 1, the inverted U-shaped strap 66 attachment mechanism of FIG. 3 is still separate from the hub ring 12, thereby still requiring its own installation time. If the fastener 74 is used to further secure the single strap 66 to the support bracket 14 the installation and removal of the strap is made more difficult and time consuming, especially in environments having limited space.
The integral attachment mechanism or straps 92 of the hub ring 76 of FIG. 4 eliminate some of the problems associated with using separate attachment mechanisms from the hub ring, however its attachment to the support bracket 14 is still difficult. Each strap 92 must be stretched during installation and removal, thus requiring more time. In addition, because the straps 92 flex away from the hub ring in their at rest or free positions, one strap must be held over one arm catch 32 while the other strap is stretched and positioned over the opposite arm catch making installation difficult.
What is needed to overcome the disadvantages of prior art hub ring attachment mechanisms is a hub ring attachment mechanism that does not require separate component parts and is automatically attached to the support bracket as the hub ring is positioned on the support bracket
The hub ring of the present invention overcomes disadvantages associated with prior art hub rings by providing a hub ring with an integral locking mechanism. The integral locking mechanism automatically locks the hub ring on the support bracket when it is properly positioned on the support surface of the support bracket. There is no need for additional attachment parts, fasteners or tools. In addition, the hub ring of the invention can be easily removed from its attachment to the support bracket by using only a prying tool, for example a small flat tip screwdriver. In the preferred embodiment of the invention the hub ring and its integral locking mechanism are constructed of a rigid but resilient plastic, thereby reducing its cost of manufacture. The hub ring of the invention is basically comprised of an annular ring having a pair of resilient, flexible arms and having three flanges that project radially outwardly from the ring where the ring, arms and flanges are all formed as a single monolithic piece.
The annular ring has a cylindrical exterior surface and an interior surface that surrounds a center opening of the ring. The exterior surface of the ring has an axial width between first and second circular end faces of the ring. A resilient vibration damper of the types employed in prior art hub rings is molded or otherwise secured to the interior surface of the ring.
A center positioning flange of the plurality of flanges extends radially outwardly from the exterior surface of the ring adjacent the ring first end face. A pair of side positioning flanges of the plurality of flanges project radially outwardly from the exterior surface of the ring adjacent the second end face of the ring. The center flange and the pair of side positioning flanges are spaced axially from each other forming a gap between the flanges at the bottom of the ring exterior surface. The gap is dimensioned sufficiently wide to receive the support bracket in the gap with the support surface of the bracket engaging the bottom of the ring exterior surface. The plurality of flanges engage against opposite first and second surfaces of the bracket on opposite sides of the bracket support surface, thereby securely positioning the hub ring on the support surface of the bracket.
The pair of resilient, flexible arms project radially outwardly from the exterior surface of the ring adjacent the first end face of the ring. The pair of arms are positioned on the ring exterior surface slightly above the pair of side positioning flanges. The arms make up a part of the locking mechanism of the hub ring. The resilient flexibility of the arms enables them to flex axially between first and second positions of the arms relative to the ring. Each arm projects radially from the ring exterior surface to a distal end of the arm and each arm has a wedge shaped barb at its distal end. Each barb has a cam surface that slides along a side of the support bracket when the hub ring is moved toward the support surface of the bracket causing the resilient arm of each locking mechanism to resiliently flex from a first, at rest position of the arm relative to the ring to a second, axially displaced position of each arm relative to the ring. Each barb also has a locking surface that passes over and engages against the latch surface of each arm catch of the support bracket when the hub ring is positioned with its exterior surface on the support surface of the support bracket. When the locking surface of the barb passes over the latch surface of the support bracket the resiliency of each arm causes each arm to flex from its second axially displaced position relative to the ring back to its first position relative to the ring, thereby positioning the locking surface of each barb beneath the latch surface of the support bracket catch arms automatically locking the hub ring to the support bracket. Each arm of the locking mechanisms is provided with a rib extending across a surface of the arm adjacent the barb. The rib engages against a side surface of the support bracket with the hub ring attached to the support bracket and maintains a small spacing between each resilient arm and the surface of the support bracket engaged by the rib. The spacing is sufficient to enable insertion of a prying tool between the resilient arm and the support bracket where the prying tool can be used to flex the arm from its first position to its second position relative to the ring, thereby enabling the ring to be removed from the support bracket.